siclick33

Only if the stab is upside down, surely? Seeing as Falcon 64 is trying to convince us of the importance of gravity verses aerodynamic forces, is it not fairly important to get the forces in the right direction?

dubd

Raf, I think I need to spend some time on the track to release some frustration.

Anyone know if FEJ is sponsoring Kentucky Jets this year?

invertmast

My Feedback: (23)

If it was a flat bottom airfoil, sure. But since it is symmetrical, it can make lift in either an upward or downward direction, depending in its angle of attack when deflected

rhklenke

My Feedback: (24)

NASA! Ha - National Association of Scale Modelers... Not the NASA he was thinking it was for sure...

Now if you read some of the papers on flutter from the NASA that he was thinking of, they say that static balancing of surfaces increases the speed at which flutter can occur, but *none* of them say that it will *eliminate* flutter which is what he claims...

A second source:

Pounding on the horse - die horsey, die...

Bob

Bob

PhilYabelli

Isin't the guy who runs Kentucky Jets sponsored by FEJ?

PhilYabelli

All this debate about flutter is nice, but there are many more problems with FlyEagle planes, and there have been from the start. Ihave only seen one or two of them fly successfully and land successfully with the gear opening and closing properly. Ihave seen a lot of these planes at the field, but it's almost always someone spending the day fooling with the plane for any number of reasons, almost never flying.

Falcon 64

Ok, a good one, at least a nice try , my bad, didn`t see it

But since we push the limit of flutter ahead of VNE, it`s a healthy thing to do, do you argee?
Ok, not on the Tomcat you say we don`t, I say we do.. We can never agree about that, I know..

If I spare someone for their future greef ( going down caused by flutter), my efforths in this is ok by me. Saving one infact would do..
But I DO hope, those who allready have a Tomcat, takes the small efforth it is to balance their elevators. It`s all you can do..
And every other scale model for that matter.
And those who feel I made enemies for themselves, well I can`t change their mind, whose aren`t my thoughts anyway.
This is just an discussion, but sometimes the glass is topped for many. That is healthy too

pip pip....

rhklenke

My Feedback: (24)

Yes, Louis is a Fly Eagle Jets "rep" (and a heck of a nice guy too). I'm not sure how much, if any, he, or anyone else, is "sponsored" by FEJ. He is *wisely* staying out of this. There is little to be gained by anyone outside of Dubd, FEJ, and the dealers involved, getting involved with this until this is resolved, IMHO...

There have been quite a few guys who have had success with some of the FEJ aircraft (although I have yet to see one last more than a few years...). On the other hand, I have no doubt that FEJ is seriously lacking in engineering talent, experience, and testing with respect to jet models. Some of us found that early with very simple models (i.e., the small F-15's, Rafaels, Liberty Jets, etc. they came out with at first), and others, like dubd, found out later with more complex/expensive models.

They are just winging it, and sometimes it works, and sometimes, it (spectacularly, in this case) doesn't. That is part of what is so frustrating...

Their planes do look pretty though...

Bob

patf

My Feedback: (4)

Dantley

find an 'arrive and drive' for this... wonders for the fun of things again..

http://www.24hoursoflemons.com/vodden13.aspx

rhklenke

My Feedback: (24)

24 hours of LeMONS - "Inexplicably presented by Car and Driver" Now that there is funny! I'll bet its a blast...

Bob

dubd

Thanks for the link! I'm on the hunt for a track car right now and will take it to Thunder Hill.

DiscoWings

My Feedback: (76)

than the plane falls down the speed of the plane doing 3d is almost zero speed so it crashes on the ground, you are more likely to insure people in the pits with a sport plane traveling at speeds than a plane doing 3d.

Obviously you have don't know much about 3d flying.

FenderBean

I guess well see since im installing the bottom missile rails and the bottom tanks on mine. I think the rear portion is strong enough, the construction of that area is built just like any other jet i have seen. The only way to improve the area would be to connect the rear stab bulkheads to the front bulkheads in the turbine bay with ply but this would add to much weight to any jet.

Falcon 64

I said wether I`m wrong or right.
Here is a reply I just got on email from Vladislav:

Vlad EFROS
00:37 (for 8 minutter siden)

til meg
engelsk
norsk Oversett e-posten
Slå av for: engelsk
Hei,

I had a look at the forum. I tried to read some aerodynamics and think about the problem. One of my conclusions is that the speed is a main factor. There is a relation between lift and weight when an unbalanced tail will not oscillate. This is because at certain angle and velocity lift will balance the weight for a higher velocity we will get oscillations. This can be a critical velocity a solution is to balance the tail. What happens if we increase the velocity more?
For NACA0009 the Cm at 1/4 chord is zero for at least +/-6 degree and the same is for Cm at aerodynamic center this mean that the tail should not oscillate if we increase the velocity.
It should be nice if you can test you profile at different velocities not just one.
There is one point of view which is right when we talk about flutter we think about the interaction between aerodynamic forces and elastic forces plus inertial forces.
Flutter= a dynamic instability occurring in an aircraft in flight at a speed called the flutter speed, where the elasticity of the structure plays an essential part in the instability=Aeroelasticity, R L Bisplinghoff.
In the same book is mentioned the concept of mass balancing wings and tails for flutter prevention in the same way that this is regularly done to control surfaces.
From the Martin Simons Model aircraft aerodynamics:
If the torsional axis of the wing, i.e. the line around which the outer panels twist, lies ahead of the wing's center of gravity, flutter is sure to occur at some speed. The stiffening should be added to he leading edge, usually in the form of sheet balsa covering and vertical spar webbing, to produce a D-shaped torsion tube. The extra weight added near the leading edge also helps to bring the center of gravity nearer to the torsional hinge line-this is an effect a partial mass balance. Other forms stiffening such as diagonal ribs or by twin twin spars with diagonal strutting internally between the spars a re less effective because they do not move the center of gravity of the structural members forward.
It is the mass of the control surface itself that is primarily responsible for the flutter and it follows that if the mass can be reduced, flutter is less likely. However, if the control can be balanced so that its center of mass, or center of gravity, is ahead of the hinge line, the inertia of the balanced surface will prevent flutter altogether.

Conclusion: mass balancing help to prevent flutter.

This is what I think or what I found so far.Flutter is a part of aeroelasticity which is quite heavy and I need more time for it.
I'll leave tomorrow to Sweden and I'll be back on 19.

invertmast

My Feedback: (23)

So static balancing wont eliminate flutter, just prolong it from happening. Assuming that the point wherre lift and weight equalize is below the max speed the model operates at.


Sounds allot like what everyone has been saying all along. That static mass balancing doesnt eliminate it, it only helps to prolong it to a higher speed.

VF84sluggo

My Feedback: (55)

As I've never seen or examined an FEJ F-14 first-hand, you would certainly know more about this than I. All I can do is offer an educated guess based on what I, and others, have observed here in video and pictures.

Good luck. I hope your assumption is correct.

Sluggo

FenderBean

Im not saying it would not do what dubds with extreme flutter but under normal flight conditions. [&:]

jlmaviation

My Feedback: (54)

Read the reply carefully -elasticity of the structure Like I said before the airframe has the structural integrity of a sponge. Elasticity = degrees of stuctural stiffness

jlmaviation

My Feedback: (54)

Here is the sneak peak of Fly Eagles' new Static Balance Structural Torsion Durability Test

koolaid535

Raf,
bring the lambo to laguna Seca, and come and grab me, i live 5 minutes away,

Manny

dubd

I deservingly got a lot of crap for saying I am thinking about getting out. I'm not going to let my enthusiasm for rc jets be faltered by FEJ and their reps. This is how I move on... by finishing my Skymaster A-10.

Zagzoo

My Feedback: (28)

Nice warthog!!

Flynstuff

My Feedback: (29)

yeahhh!!!

Shaun Evans

Dear Falcon,

How exactly does one put the center of gravity and/or the center of mass "ahead of the hinge line" on a full-flying stab?

The type of mass-balancing referred to there is like that which is done on MANY (if not most) hinged control surfaces like ailerons and elevators. We're talking full-flying stabs here, so let's not let the truth get lost in translation.

crashgoodly

what a lovely way to burn kero. nice to see the thick skin of the modeller coming through.